Stepped Care for Posttraumatic Stress Disorder Study

This study uses a Sequential, Multiple Assignment, Randomized Trial (SMART) design. All participants enrolled will receive access to webSTAIR at baseline ("initial treatment"). Nonresponders at 4 weeks are randomized to either continue webSTAIR or webSTAIR plus community health worker coaching ("stage 1 treatments"). Nonresponders at 8 weeks are re-randomized to clinician-administered treatments, either Brief STAIR or WET ("stage 2 treatments"). Nonresponse is defined as less than a 15-point decrease in PTSD symptom severity, as measured by the PTSD Checklist for DSM-5 (PCL-5). The objectives of this study are to: * examine the main effects of stage 1 treatments, stage 2 treatments, and embedded * adaptive interventions on PTSD symptom severity. * confirm mechanisms of change established in the extant PTSD literature * identify patient-level moderators of change in PTSD symptoms severity at 18 weeks